1. Field of Invention
The present invention generally relates to an electrical connector applied to transmit electrical signals, and more particularly relates to an electrical connector which can reduce cross talk induced by closely spaced contacts, enhance transmission performance, and meet the EIA/TIA, Category 5e, standard.
2. Related Art
Information transmissions through network communication are recently more and more popular. The applications are getting wider. As a demand, the high speed and high efficiency transmissions require high quality cabling and connectors. Generally, the network communication paths are composed of transmission media and electrical connectors. On the transmission media, there are twisted pair cables, coaxial cables, and optical fibers. There are a certain defects occurred in the communication paths which will get worsen as the frequency of signals getting higher. The defects may come from:
1) cross talk, which is induced by electromagnetic interference between closely spaced cables or contacts;
2) return loss, which is caused by reflections in the communication system due to the discontinuous impedance; and
3) attenuation of signal. The level of signal decreases when the transmission distance increases.
Taking unshielded twisted pair (UPT) cabling for example, the cable includes two isolated copper wires twisted with a certain pitch and a certain manner. A pair or two pairs of twisted cables constitute a communication chain as a simplest transmission medium. The twisted pairs are commonly used in computer communication networks. But, in their connecting hardware, cross talk is induced due to capacitive and inductive couplings between adjacent conductors. As the frequency of the signal increases, the magnitude of the cross talk is logarithmically increased, and the impedance also increases, which badly distort the high frequency signals.
For the aforesaid reasons, the EIA/TIA 568 standard established by Electronic Industries Association has been adopted into IEEE 802.3u standard by the Institute of Electrical and Electronics Engineers, Inc. The IEEE 802.3u standard includes all the standards for the transmission medium and connectors, and classifies them into several categories. For example, xe2x80x9cCategory 3xe2x80x9d are network cabling for voice which use solid copper wires of 24AWG with impedance 100xcexa9 and certifies UTP for data transmission up to 10 Mbps; xe2x80x9cCategory 4xe2x80x9d are the same as Category 3 but with data transmission up to 16 Mbps; xe2x80x9cCategory 5xe2x80x9d are the same as Category 3 but with data transmission up to 100 Mbps. Another category with tighter requirements than Category 5 is xe2x80x9ccategory 5exe2x80x9d which requests for a limited extent of return loss caused by reflections in the communication system due to the discontinuous impedance.
There have been prior arts to solve the problem of decreased performance in transmitting higher frequency signals. For example, in U.S. Pat. No. 4,648, 678, the adjacent terminals for a connector are settled on two different planes. A further improvement of connector disclosed by U.S. Pat. No. 5,674, 093 is to differentiate the bending angles of adjacent terminal legs, so that the adjacent terminal legs are not parallel to each other, and, the electrical signal transmission characteristics of said connector is enhanced. The terminal legs in these connectors have sharp angle bends to be contacted with contact ports of a terminal plug. Since the terminal legs are all located aside the connector body, the terminal legs will have different distances from two sideward connecting posts on the printed circuit board when the connector is being mounted in center of a printed circuit board. As a result, the different distances cause unbalanced paths and unequal cross talk on two sides.
It is therefore an object of the present invention to provide an electrical connector which can improve communication quality for higher frequency transmission and meet the requirement of Category 5e in EIA/TIA standard.
To achieve the aforesaid objects, an electrical connector capable of reducing cross talk according to the present invention includes a body and a plurality of metal wires. The body is composed of a seat, a pressing element and a cap. The seat is formed with a plurality of grooves where adjacent grooves are located in two different planes. The wires are mounted into the grooves so that adjacent wires are located in different planes so as to reduce cross talk. Those parallel wires located in a same plane are formed into a necked portion so as to enhance compensation, improve the transmission performance and meet the requirements of Category 5e in EIA/TIA standard.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.